One reason the cultures of north africa developed differently from the cultures of the rest of africa was that these areas of africa were separated by the
a) arabian sea.
b) sahara desert.
c) congo river basin.
d) great rift valley.

answer: this problem has only trivial solutions, with all points on the same line. x=5 or x=7/5.

step-by-step explanation:

there are three triangles, and three unknowns: x, y=length of middle segment, and z=cos(angles marked with red arc).

we need

and law of cosines,

the three equations are

see attached image for solution.